High voltage electric circuit interrupter



June 27, 1939. E. J. FRANK' lHIGH VOLTAGE ELECTRIC CIRCUIT INTERRUPTER Imverwtor". Edward .IFrar-mk, by @CTM A HIS Attorney.

Patented June 27, 1939 UNITED STATES PATEN'I OFFICE HIGH VOLTAGE ELECTRIC CIRCUIT INTEBRUPTER Edward J. Frank, Yeadon, Pa., assignor to General ElectricCompany, 'a corporation of New- York My invention relatesto electric circuit interrupters for highvoltage power circuits, more particularly to high speed electric circuit breakers of the liquid blast type for opening a high lvoltage alternating current power circuittwithin a few cycles.

In the 'operation of high speed circuit breakers of the aforesaid type, the main problem is to create an arc-interrupting liquid blast in as short a 'time as possible after the tripping impulse causing separation of the breaker contact structure. In a well-known form of oil blast breaker the separation of the relatively movable contact structure in response to the tripping impulse results progressively in two arcs in series, the iirst of which is utilized as a pressure generating arc for vdriving arc-extinguishing liquid `through the other arc. Accordingly in this form ci circuit breaker, although the interrupting action is positive and'very reliable, the interrupting blast is not made effective until the second arc has been drawn.- This is a particularly important considthe liquid dielectric with respect to high voltages.

This isolating distance is considerably greater than the amount of separation required for actual arc interruption.

The principal object of my invention is the provision of an improved. high speed electric circuit interrupter of the liquid blast type which is effective to cause an arc-interrupting liquid blast immediately upon initial separation of the relativelymovable contact structure and prior to the isolating operation. More specitlcally,'a further object is the provision of an improved high speed multiple-break oil circuit breaker of the explosion chamber type Iwherein the arc-interrupting blast y is created and'applied immediately upon initial circuit opening movement and separation of the c'cntactstructure, and wherein the ilxed and movable terminals are isolated within the oil breaker casing substantially independently of the circuit interrupting operation.

In 'accordance' with a preferred embodiment of my invention the contact structure is arranged to form a plurality of breaks in series and is disposed Within an explosion chamber immersed in oil havthe contacts under the influence of a main movable contact memberdisposed exteriorly of the explosion chamber. Upon initial contact separation arc pressure formed in the explosion chamber drives oil through those arcs adjacent the chamber exhaust ports and the circuit is interrupted at these points. Further limited separation of the contacts within the explosion chamber takes place and is followed by separation of the main movable contact member from the contact structure in the explosion chamber, so that an isolating break exteriorly of the explosion chamber is formed thereby. In the circuit closing operation the movable contact member is raised in the oil so as first to close the isolating gap and then bias the contacts Within the explosion chamber into engagement.

My invention will be more fully set forth in the following description referring to the accompanying drawing, and the lfeatures of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specication.

Referring to the drawing the single ligure thereof is an elevational View,A partly in section, of one pole of an oil circuit breaker embodying the present invention.

The drawing illustrates one pole of an oil circuit breaker of the type wherein a pair of xed contact structures, one of which is indicated at I, arey interconnected by a bridging member 2 in the closed circuitposition. The bridging member 2 is operated vertically by a lift-rod-3 for opening and closing the breaker. The iixed contact structure i comprises essentially a pressure-confining chamber which is formed, in the present instance, by a cylindrical insulating member 4 composed of a mechanically strong insulating material such as ber, for example. The chamber so formed is substantially closed at its opposite ends and is immersed in a suitableh insulating and arc-extinguishing liquid such as oil.

For the purpose of forming a plurality of breaks in series within the chamber, contact structure mounted for limited movement is disposed therein comprising contact bridging members 5, 6 and 1.

"I'hese contact members are each resiliently mounted on an insulating operating rod 8 and engage respectively pairs` of fixed contacts suit- 'any mounted in the side wens of the innnating casing 4. More specifically. the contact member 5 coacts with contacts 9 and I0, the contact 5 with contacts II and I2 and the contact 1 with 'contact I3. The lower contact 1 is electrically connected through a iiexible conductor I4, to a butt contact .member I5 mounted at the lower end .of `rod I which is adaptedto be engaged by the contact element 2' ci the bridging member 2.

The circuit through the breaker in the closed circuit position beginning with the iixed terminal structure generally indicated at I5 'comprises a conductor I'I interconnecting the Aterminal structure and the contact 9, contacts 5 and Ill, conductor I8 interconnecting contacts I0 and I2. contacts 6 and II, conductor I9 interconnecting contacts Il and I3, contacts I and I 5 which are interconnected by the exible conductr I4, movable contact 2' and the main bridging member 2,

The conductorsl I8 and I9 which extend along theinner walls of casing 4 are suitably insulated from the interior of the chamber by insulating strips I8 and I9' respectively.

The contacts 5v, 5 and 1 which are mounted on the insulating operating rod 8 operate as a unit. the unit being normally biased by a spring 2l' toward the open-circuit position. The breaker is held in the closed circuit position by the bridging member 2 which engages the lower end of the rodl through the butt contact I5, so as to bias the aforesaid contact unit upwardly against the'bias oi spring 20 into contact-making engagement. j

Referring more particularly to the specific structure employed in the present instance, the fixed terminal structure at I5 comprises an adapter v2| which is connected in a well-known manner -to the lower end oi the lead-in conductorand bushing extending through the circuit breaker tank cover. The insulating cylinder 4 is suitably clamped as at 22 to the adapter so as to extend in vertical depending relation therewith. 'Ihe casing 4 can also be secured in position if desired by insulating rods Vextending from the adapter to the lower end of the casing.

v Secured to the upper end of the insulating rod 8 is a thimble 23' slidable in a piston-like man-- nerlwithin a vented cup-like member 24 which is biased by the spring 28 so as to be in abutting engagement lwith the thimble 23. The spring 20 is seated at one end on the adapter 2| and at the other end on a disk or piston member '25 which is secured to the member 24 and is guided in turn within a sleeve 28 which is supported in.

depending relation as' illustrated fromvthe adapter' 2|.

Springs 2! towards 7o equauuesin spacing or 'the Vto\ prevent excessive chock It. will, therefore-be noted that'the cup member 24',A under the bias oi spring' 2|.can'urge the insulating rod 8 .downwardly and1 that the insulating rod, if-impelled downwardly-by other forces, can operate. without restraiht'by -re'asonj' of the sliding connection between`the 23 and 24.

The bridging coni-.act inemnennnrneaey dal." rod t have limited movementgas deiinecl by vthe stop members 21 and 2l connection ischleny'tcr .the ing suiilclent contact wipe 'atthe contacts in order to' compensate-ier: llilht incontacts'andincrde'r cum meenam.

thecasinghcsubstantiall! closing operation.

lower part o:

closed by the butt contact I5 which is mounted on the rod 8 and an end cap 30 which is suitably secured at 3l to the insulating cylinder. The butt contact I5, which is formed as a cup-shaped member is also biased by springs 32 so as to have a limited wipe at 33 with respect to vthe operating rod 8. Accordingly, the springs 32 allow over-travel of the butt' contact yI5 without necessarily afiecting'the contacts within the arc chamber.

For the purpose of utilizing the arc pressure generated within` the chamber immediately upon initial separationi of the contacts there are provided exhaust ports in the chamber walls opposite certain of the breaks, so that the arc pressure created within the chamber at other breaks is eiiective to drive oilvthrough the exhaust ports ior'interrupting the arc at those points. In the present arrangement a pair of diverging ports 34 for splitting the arc into two sections are located adjacent and immediately opposite the break between the contacts 5 and 9 so that arc pressure within the casing tends to drive two jets 'o f oil transversely across the arc at said break. Similarly, exhaust ports are disposed ati-35 and 38 opposite the breaks atv the contacts 6 and I2 and at the contacts 1 and I3 respectively, The ports within the chamber are faced with suitable arc-resisting insulating material indicated at 34', 35' and 36 respectively. Accordingly the arc pressure generated at the breaks 5I0 and B-ll is eiIective' to drive oil from the arc chamber through the exhaust ports above described for interrupting the arc at a plurality of points. It shall be understood,v of course, that the number of breaks, including the pressure generating breaks, can be varied to meet the interrupting requirements of the breaker.

Since the interrupting operation above described takesplace immediately after the main bridging member 2 has dropped but a short distance, it will be apparent that the time of sepasecured to the operating rod 8 limits the lower travelo! the contact unit at the end cap 30. The bridging member can then be separated the desired isolating distance within the oil from theJ iixed explosion chamber structure.

vDuring the circuit-opening operation the disk or pistom member 25 which is biased downward by the'spring 20 serves also 'to .the exhaust ports oi the explosion chamber. This auxiliaryaction is particularly helpful in the case of weak or moderate currents which are sometimes ineilective to create the desired blast presoi large or short circuit currents the arc pressure created -within the chamber tends to urge the operating rod 8 and the structure associated .therewith downward through the opening in the L endcap 3l. In such cases the sliding connection the operating rod, .and are'vncrmdly pendent downward movement of the rod 8 notwithstanding reverse'movement of the piston 25 .between thelrod 8 and piston125 provides for indearc pressure at high currents may actually speed drive oil through sure within the explosion chamber. In the case up the separation of the contacts and interruption l o! thecircuit. This downward movement of the rod l can also be independent of the bridg- .75A

ing member 2 by reason of the resilient connection at 32 `It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and m'odiiicati'ons may occur to one skilled in the art without departing from the spirit of my invention.

-What I claim as new and desire to secure by Letters Patent of the United States, is:

1. An electric circuit breaker of the liquid blast type comprising an arc-'extinguishing liquid, relatively movable contact structure adapted to separate in said liquid to vform a pressure-generating `break and an interrupting break, piston structure for also projecting a stream of said liquid into an arc formed at said interrupting break upon sepa- Y ration oi' 4said contact structure, energy-storing of the arc-interrupting contact structure.

means for operating said piston, and means associated with the movable contact structure for charging said energy-storing means during thev circuit-closing operation prior to actual engagement oi the contact structure whereby in case of a short circuit a liquid blast through said interrupting break is immediately available upon restoring means for operating said piston, and

means connected to the movable contact structure oi said isolating contacts arranged to cause charging .of said energy-storing means and resetting oi said piston in accordance with the circuit-closing operation prior to actual engagement 3. An electric circuit breaker comprising a casing containing an arc-extinguishing liquid, Ilxed and movable contacts arranged to separate in said casing to interrupt arcing, a piston disposed in said casing and operativelyA related to the movable contact structure, a spring associated with said piston for causing a blast of said liquid throughan arc formed upon separation of said o contacts, and isolating contact structure disposed exteriorlygoi said casing for depressing said pis-v ton and charging said spring during the circuitclosing operation prior to actual engagement of said arc-interrupting contacts.

A4. An electric circuit breaker oi the liquid blast type comprising a .pressure-commingchamber containing an arc-extinguishing liquid, relatively movable contacts separable within said chamber to form a pressure-generating arc. and an interrupting arc subject to a liquid blast.' a piston independent of said contacts communicating with said chamber, a spring for biasing said piston in a direction also to cause a liquid vblast through said interrupting arc independently of said pres sure-generating arc, said piston being in free I ollowing relation to the movablercontact structure,

and means foractuating said movable contact structure to closed circuit position whereby. laid piston is returned to its spring-charged position,-

prior to engagement'of said contacts.V

`5.` An electriccircuit breaker of the liquidblast type comprising an arc-extinsuishins liquid. rela-l tively vilxed contact structure immersed in said liquid including an insulating casing forming a chamber, of bridgbetween the rod and the butt contact ing contacts mounted for limited movement within said chamber, each bridging contact coacting with iixed contact structure mounted in said casing to form two breaks in series, means for interconnecting said fixed'and movable contacts to form a plurality of breaks in series in the circuit within said chamber, said casing having exhaust ports adjacent and opposite certain of said breaks so that arc pressure 'created within said c chamber is eiective to drive arc-extinguishing liquid through the arcs at said breaks, an insulating member on which said bridging contacts are mounted foriuniform movement therewith, spring means biasing said insulating member lin a direction to open the circuit at said breaks, a contact member mounted with respect to said insulating member and electrically connected in series with said contacts, and a main movable breaker member 'operable in the arc-extinguishing liquid exteriorly of said chamber for engaging said last-named contact and biasing said insulating member against said spring means towards closed circuit position, initial opening movement of said main member causing interruption of the circuit within said chamber prior to separation of said -member and its coacting contact. l

6. An electric circuit breaker of the liquid blast type comprising an insulating casing forming a pressure-conning chamber containing an arc extinguishing liquid, relatively movable contacts separable within said chamber, said chamber having an exhaust port adjacent and opposite a break formed by separation of said contacts so that arc pressure created within said chamber upon opening of th'e circuit is eiective to drive liquid through the arc at said port, a contactactuating member connected to said contact structure, arc pressure in said chamber tending to move said actuating member toward open circuit position, a pistonfor augmenting the arc pressure in said chamber, and spring means for piston.

'1. An electric circuit breaker of the liquid blast type comprising an arc extinguishing. liquid, relatively iixed contact structure immersed in said liquidincluding an insulating casing forming a pressure confining chamber, a plurality of bridg- -ing contacts mounted for limited movement within said chamber, each bridging contact coacting with xed contact structure mounted in said casing to form two breaksv in series, means for electrically interconnecting said xed and movable contacts to form a multiplicity of breaks in `series in the circuit within said chamber, said casing` having an exhaust port adjacent and opposite one break at each bridging contact so that arc pressure created within said. chamber is effective to drive arc extinguishing liquid through the arcs at said breaks, said exhaust ports alternating at opposite sides of said chamber, an insulating member with respect to which said bridging contacts 'are mounted for substantially uniform movement therewith, spring means biasing said insulating member in a direction to open the circuit 'at said breaks, a contact member mounted with respect to said insulating member and electrically connected inhseries with said contacts, and a main movable circuit breaker member operable in the arc-extinguishing liq- -uid exteriorly of said chamber for engaging said 'last-named contact and biasingv saidvinsulating member against said spring means towards closed circuitA position whereby initial opening movement of said main member causes interruption of the circuit within said chamber prior to separation of said member and its coacting contact. 8. An electric circuit breaker of the liquid blast type comprising an arc extinguishing liquid, relatively fixed contact structure immersed in said liquid including insulating chamber structure forming pressure conning means, a plurality of Ibridging contacts mounted for limited moveadjacent and opposite one break at each bridging contact so that arc pressure created at the other break within said pressure confining means is eiiective to drive arc liquid .through the arcs ateach'of said exhaust port breaks, an insulating member with respect to which said bridging contacts are mounted for Ysubstantially uniform movement therewith,

spring means biasing said insulating member in a direction to open the circuitat said multiplicity of breaks, a contact member `mounted with respect to said insulating member and electri. cally connected in series with the contacts in said pressure conining means, and a main movable circuit breaker member operable in the arc-- extinguishing liquid exteriorly of -said pressure conning means for engaging said last-named contact and biasing said insulating member against said spring means towards closed circuit position whereby initial opening movement of said main member causes interruption of the circuit within said pressure connng means prior to separation of said member and its contact.

nnwann'q. maux. 25 

